Aging gametes in relation to incidence, gender, and twinning in Down syndrome

Abstract

Sexual practices have been implicated in the causation of Down syndrome (DS). Two mechanisms have been hypothesized. The theory of the fertilisation of an overripe ovum due to a delay in fertilization, and more recently the aging of the sperm. The orthodox Jewish population have very specific, strict practices concerning menstruation, which provide a unique model for the study of births in relation to time of conception. Data on the incidence of DS in the Jewish population of Jerusalem between 1982 and 1988 were analyzed. Among a comparable group of mothers under age 37 years and for whom amniocentesis was not available, it was found that the incidence of DS was significantly higher in the religious than in the nonreligious population (P less than 0.001). The rate of twinning in the DS population was significantly higher than in the general population (P less than 0.015), as was the ratio of males to females, 62% and 38%, respectively compared with 51% males and 49% females in the newborn population (P less than 0.001). The association of these 3 factors in relation to the aging gamete of either maternal or paternal origin is discussed.

Gender Affects Clinical Suspicion of Down Syndrome

“…Analysis showed that this increase was accounted for by the growing use of karyotyping to confirm the diagnosis. Among individuals with a clinical diagnosis only, sex ratio was 0.97 (1160 males/1198 females) [Collman & Stoller, 1962;Davidenkova et al, 1965;Huether, 1990;Kovaleva et al, 2001;Staples et al, 1991] while among individuals with confirmed trisomy 21 this figure was 1.31 (1918 males/1466 females) [Huether, 1990;Kovaleva et al, 2001;Mikkelsen et al, 1976;Mikkelsen et al, 1990;Sharav, 1991;Staples et al, 1991;Stoll et al, 1990;Wahrman & Fried, 1970]. Correspondingly, in samples where proportion of clinical diagnosis only was 30% and more, intermediate figure of 1.12 (1950 males/1742 females) [Baird & Sadovnik, 1987;Christoderescu et al, 1977;Johnson et al, 1996;Kallen et al, 1996;Kovaleva et al, 2001;Staples et al, 1991] was observed.…”

Review of epidemiological factors (other than maternal age) that determine the prevalence of common autosomal trisomies

“…However, the review concluded that rates for different populations were unlikely to vary by more than about 25%. Some differences could be attributable to ethnically related sexual practices leading to infrequent intercourse 21,22 . Contemporary estimates of birth rates are confounded by use of prenatal screening, diagnosis, and pregnancy intervention.…”

Prenatal Diagnosis and Screening for Down Syndrome

“…confirm the diagnosis. Among individuals with a clinical diagnosis only, sex ratio was 0.97 (1160 males/1198 females) [Collman & Stoller, 1962;Davidenkova et al, 1965;Huether, 1990;Kovaleva et al, 2001;Staples et al, 1991] while among individuals with confirmed trisomy 21 this figure was 1.31 (1918 males/1466 females) [Huether, 1990;Kovaleva et al, 2001;Mikkelsen et al, 1976;Mikkelsen et al, 1990;Sharav, 1991;Staples et al, 1991;Stoll et al, 1990;Wahrman & Fried, 1970]. Correspondingly, in samples where proportion of clinical diagnosis only was 30% and more, intermediate figure of 1.12 (1950 males/1742 females) [Baird & Sadovnik, 1987;Christoderescu et al, 1977;Johnson et al, 1996;Kallen et al, 1996;Kovaleva et al, 2001;Staples et al, 1991] was observed.…”